For a traditional vertical alignment (VA) liquid crystal display device, when a picture is displayed, liquid crystal molecules maintain a certain deflection angle, such that transmittances of light under different viewing angles are different, as a result, a color cast phenomenon that a user will feel different colors of the picture when viewing the picture in different viewing angles is caused.
In order to improve the problem of color cast, a common method at present is to divide pixel electrodes of RGB sub-pixels in each pixel unit into two independent pixel electrodes and to apply different drive voltage to the two pixel electrodes respectively to improve the problem of color cast. For the method, since an amount of the pixel electrodes is increased, more metal wires or thin film transistor (TFT) elements need to be redesigned to drive a display panel, but the metal wires and TFT elements are light-shielding, thus this method will scarify a light transmitting aperture region, affects a transmittance of the panel and increases a backlight cost.
In order to avoid the increase of the metal wires or TFT elements, another method is to apply two kinds of high and low drive voltage signals to every two pixel units respectively. Specifically, at a same moment, drive voltages of different polarities are applied to every adjacent two sub-pixels. By adopting such a manner, mismatch of the high voltage positive and negative polarities of a same row of sub-pixels will be caused, that is, an amount of the sub-pixels of a positive polarity high voltage is inconsistent with an amount of the sub-pixels of a negative polarity high voltage. Hence, due to an influence of stray capacitance, when the amount of the sub-pixels of the positive polarity high voltage is more than the amount of the sub-pixels of the negative polarity high voltage, the equivalent voltage of a common voltage Vcom is improved compared with the original Vcom, as a result, actual charging charges of the sub-pixels of the positive polarity high voltage are increased, and the brightness is increased, and on the contrary, actual charging charges of the sub-pixels of the negative polarity high voltage are increased, and the brightness is reduced, thereby further affecting display colors and a picture quality, and generating the problem of abnormal picture quality output.